I wonder if its calcium carbonate or calcium citrate. I suspect the former, only because it is cheaper. Low calcium causes neuromuscular irritability and cramps but usually the main mechanism of cramping after sustained excercise is from low magnesium or potassium.
Perhaps the carbonate in the rennie provides a good base buffer but physiologically, one tablet and its absorption should not affect the lactic acid buildup. Bicarbonate, specifically sodium bicarbonate is an alkalising agent and therefore reduces the acidity of the blood (known as a buffering action). However, the clinical research I've seen that showed any improvement in lactate threshold involved loading up with 4grams/day of sodium bicarbonate for six days before it was able to improve VO2max by 9% and the Lactate Threshold raised by 12% .
Not sure why the rennie would work so fast. Did you or he consume something else with it?
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Last edited by cbhungry; 10-24-03 at 06:26 AM.